Light emitting module and planar light source

ABSTRACT

A light emitting module including: a light guide member including: an emission region defined by a sectioning groove, a light source placement part located in the emission region, and a light adjusting hole; and a light source disposed in the light source placement part. In the schematic top view: the light adjusting hole is not positioned on a first straight line connecting (i) a center of the light source and (ii) a point in the sectioning groove that is farthest from the center of the light source, and a first lateral face of the light adjusting hole has a first region, and a line normal to the first region is oblique to a second straight line connecting (i) the center of the light source and (ii) a point in the sectioning groove that is closest to the center of the light source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2020-019416 filed on Feb. 7, 2020, and Japanese Patent Application No.2020-169824 filed on Oct. 7, 2020, the disclosures of which are herebyincorporated by reference in their entireties.

BACKGROUND

The present disclosure relates to light emitting modules and planarlight sources.

Planar light sources that employ light sources and light guide membershave been used as backlights for liquid crystal displays. For planarlight sources, techniques for sectioning an emission face into multipleemission regions and controlling the luminance per emission region havebeen developed. See, for example, Japanese Patent Publication No.2008-59786. There is a need to reduce luminance non-uniformity in eachemission region.

SUMMARY

One of the objects of certain embodiments of the present invention is toprovide a light emitting module and a planar light source in whichluminance non-uniformity in emission regions is reduced.

A light emitting module includes: a light guide member comprising: anemission region defined by a sectioning groove, a light source placementpart located in the emission region, and a light adjusting hole,wherein, in a schematic top view, the light adjusting hole is locatedbetween the sectioning groove and the light source placement part; and alight source disposed in the light source placement part. In theschematic top view: the light adjusting hole is not positioned on afirst straight line connecting (i) a center of the light source and (ii)a point in the sectioning groove that is farthest from the center of thelight source, the light adjusting hole has a first lateral face locatedon a side closer to the light source and a second lateral face locatedon a side opposite the first lateral face, the first lateral face has afirst region, and a line normal to the first region is oblique to asecond straight line connecting (i) the center of the light source and(ii) a point in the sectioning groove that is closest to the center ofthe light source.

A light emitting module includes: a light guide member comprising: anemission region defined by a sectioning groove, a light source placementpart located in the emission region, first light adjusting hole, and asecond light adjusting hole, wherein, in a schematic top view, the firstlight adjusting hole and the second light adjusting hole are locatedbetween the sectioning groove and the light source placement part; and alight source disposed in the light source placement part, wherein: arefractive index of an inside of the second light adjusting hole islower than a refractive index of the light guide member. In theschematic top view, a shape of the emission region is quadrilateral. Thefirst light adjusting hole is not positioned on a first straight lineconnecting a center of the light source and a corner of the emissionregion where light emitted from the light source is totally reflected bya lateral face of the first light adjusting hole. The second lightadjusting hole is positioned at a region with which the first straightline intersects where the light emitted from the light source isrefracted in the second light adjusting hole.

A planar light source according to one embodiment includes the lightemitting module described above and a wiring substrate. The light guidemember is disposed on the wiring substrate. The light source is mountedon the wiring substrate.

According to the embodiments, a light emitting module and a planar lightsource in which luminance non-uniformity in emission regions is reducedcan be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic top view of a planar light source according to afirst embodiment.

FIG. 2 is a schematic top view of an emission region of the planar lightsource according to the first embodiment.

FIG. 3 is a schematic cross-sectional view of the planar light sourceaccording to the first embodiment taken along line III-III in FIG. 1 .

FIG. 4 is a schematic top view of an emission region of a planar lightsource according to a second embodiment.

FIG. 5 is a schematic top view of an emission region of a planar lightsource according to a third embodiment.

FIG. 6 is a schematic top view of an emission region of a planar lightsource according to a fourth embodiment.

FIG. 7 is a schematic top view of an emission region of a planar lightsource according to a fifth embodiment.

FIG. 8 is a schematic top view of an emission region of a planar lightsource according to a sixth embodiment.

FIG. 9 is a schematic top view of an emission region of a planar lightsource according to a seventh embodiment.

FIG. 10 is a schematic top view of an emission region of a planar lightsource according to an eighth embodiment.

FIG. 11 is a schematic cross-sectional view of a planar light sourceaccording to a first variation.

FIG. 12 is a schematic cross-sectional view of a planar light sourceaccording to a second variation.

FIG. 13 is a schematic cross-sectional view of a planar light sourceaccording to a third variation.

FIG. 14 is a schematic cross-sectional view of a planar light sourceaccording to a fourth variation.

FIG. 15 is a schematic cross-sectional view of a planar light sourceaccording to a fifth variation.

FIG. 16 is a schematic cross-sectional view of a light emitting moduleaccording to a sixth variation.

FIG. 17A is a schematic cross-sectional view of a light source accordingto a seventh variation.

FIG. 17B is a schematic cross-sectional view of a light source accordingto an eighth variation.

FIG. 17C is a schematic cross-sectional view of a light source accordingto a ninth variation.

FIG. 18A is a schematic cross-sectional view of a light source accordingto a tenth variation.

FIG. 18B is a schematic cross-sectional view of a light source accordingto an eleventh variation.

FIG. 18C is a schematic cross-sectional view of a light source accordingto a twelfth variation.

DETAILED DESCRIPTION First Embodiment

A first embodiment will be explained first.

FIG. 1 is a top view of a planar light source according to theembodiment.

FIG. 2 is a top view of an emission region of the planar light sourceaccording to the embodiment.

FIG. 3 is a cross-sectional view of the planar light source according tothe embodiment taken along line III-III in FIG. 1 .

As shown in FIG. 1 to FIG. 3 , the planar light source 1 according tothe present embodiment has a wiring substrate 200, and a light emittingmodule 100 is disposed on the wiring substrate 200. In the lightemitting module 100, a light guide member 20 and light sources 30 aredisposed. The light guide member 20 is disposed on the wiring substrate200, and the light sources 30 are mounted on the wiring substrate 200.

In the wiring substrate 200, a wiring layer 202 and a connection layer203 that electrically connects the wiring layer 202 and the lightsources 30 are provided in an insulating base material 201. In FIG. 3 ,only one wiring layer 202 is shown, but multiple wiring layers 202 canbe disposed. An adhesive sheet 205 and a light reflecting sheet 206 aredisposed between the wiring substrate 200 and the light guide member 20.The adhesive sheet 205 adheres the wiring substrate 200 and the lightreflecting sheet 206. The light reflecting sheet 206 reflects a portionof the light emitted from a light source 30.

For the light reflecting sheet 206, a resin sheet containing a largenumber of air bubbles (e.g., foamed resin sheet), a resin sheetcontaining a light diffusing material, or the like can be used. For theresin used as the light reflecting sheet 206, a thermoplastic resin,such as an acrylic resin, polycarbonate resin, cyclic polyolefin resin,polyethylene terephthalate resin, or polyester resin, or a thermosettingresin, such as an epoxy resin or silicone resin, can be used. For thelight diffusing material, any known appropriate material, such astitanium oxide, silica, alumina, zinc oxide, or glass, can be used.

On the upper face of the wiring substrate 200, a light reflecting layerhaving light reflectivity for the light emitted from the light sources30 can further be disposed, and in this case, the adhesive layer 205 isadhered to the light reflecting layer. Alternatively, the lightreflecting layer can be disposed between the light guide member 20described later and the light reflecting sheet 206, for example, on theupper face of the light reflecting sheet 206. This allows the lightreflecting layer to scatter a portion of the light that is emitted fromthe light sources 30 and propagates in the light guide member 20,thereby facilitating the extraction of light from the upper face of thelight guide member 20. Such a light reflecting layer can have a film ordot shape. The light reflecting layer can extend into the light sourceplacement parts 22 of the light guide member 20 described later whenviewed from above. Preferably, the light reflecting layer is extended tothe positions that overlap the light sources 30 when viewed from above,i.e., between the light sources 30 and the wiring substrate 200. Thiscan hinder the wiring substrate 200 from absorbing a portion of thelight emitted from the light sources 30, thereby moderating theluminance decline around the light sources 30.

For the light reflecting layer, for example, a resin containing anyknown appropriate light diffusing material, such as titanium oxide,silica, alumina, zinc oxide, or glass, can be used. For the resin usedas the light reflecting layer, similarly to that used as the lightreflecting sheet 206, a thermoplastic or thermosetting resin, forexample, can be used. For the resin used as the light reflecting layer,a UV curable resin can alternatively be used.

The light guide member 20 is formed of a light transmissive material,and is plate shaped, for example. For the material used as the lightguide member 20, for example, a thermoplastic resin, such as an acrylicresin, polycarbonate resin, cyclic polyolefin resin, polyethyleneterephthalate resin, or polyester resin, a thermosetting resin, such asan epoxy resin or silicone resin, or glass can be used. In the lightguide member 20, sectioning grooves 21, and emission regions R definedby the sectioning grooves 21 (i.e., the sectioning grooves 21 sectionthe emission regions R), light source placement parts 22 positioned inthe emission regions R, and light adjusting holes 23 each providedbetween the light source placement parts 22 and corresponding one of thesectioning grooves 21 when viewed from above are formed. The thicknessof the light guide member 20, for example, is preferably 200 μm to 800μm.

In the present disclosure, for the purpose of explanation, an XYZorthogonal coordinate system is employed. The direction in which thewiring substrate 200 and the light guide member 20 are layered isdenoted as the “Z direction” and the directions in which the emissionregions R are arrayed are denoted as the “X direction” and the “Ydirection.” With respect to the Z direction, the direction from thewiring substrate 200 to the light guide member 20 will also be denotedas the “upward direction” and the opposite direction will also bedenoted as the “downward direction.” These expressions, however, areused for the sake of convenience, and have nothing to do with thedirection of gravity. Viewing of an object from the upper side will beexpressed as “when viewed from above.”

When viewed from above, the sectioning grooves 21 form a lattice shapeextending in the X direction and the Y direction, individuallysurrounding the emission regions R. The formation of the sectioninggrooves 21 is not limited to a lattice, as long as they can opticallydivide the emission regions R to a practically sufficient extent. Forexample, the sectioning grooves do not have to be provided at thelattice points. This allows the light from adjacent emission regions Rto be collected in the regions including no sectioning groove, therebypreventing the corners of the emission regions R from becoming lessluminous. The explanation will be given below using a single emissionregion R, that similarly applies to the other emission regions R.

The width of a sectioning groove 21, for example, can be set to about 5%at most of the width of an emission region R. In the case of disposingthe sectioning member 21 a described later in the sectioning groove 21,it is preferable to set the width of the sectioning groove 21 to make iteasy to dispose the sectioning member 21 a. The sectioning groove 21 canoccupy any appropriate percentage of the light guide member 20 in thethickness direction (Z direction). For example, in the case of reducinglight leakage between adjacent emission regions R, the sectioning groove21 preferably occupies at least 50% of the thickness of the light guidemember 20, more preferably at least 70%, particularly preferably atleast 90%.

As will be explained later with reference to variations of theembodiment, each sectioning groove 21 can be formed on the upper face 20a or the lower face 20 b of the light guide member 20, formed to passthrough the light guide member 20 in the Z direction, formed as a shapein which a through groove is partially closed, or as a hollow space notreaching the upper face 20 a or the lower face 20 b of the light guidemember 20. A hollow sectioning groove 21 can be formed, for example, byadhering together a light guide plate whose upper face has a groove anda light guide plate whose lower face has a groove by using a lighttransmissive adhesive sheet. The same material as that used for thelight guide member 20 is preferably used for such an adhesive sheet soas to reduce a possibility that any interface between the layers iscreated. In the present embodiment, for example, each sectioning groove21 is formed on the upper face 20 a of the light guide member 20.

The inside of each sectioning groove 21 can be an air layer, or includea sectioning member 21 a containing a light reflecting material. For thelight reflecting material, for example, a metal or a resin containing alight diffusing material can be used. For the resin used as the lightreflecting material, a thermoplastic resin, such as an acrylic resin,polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalateresin, or polyester resin, or a thermosetting resin, such as an epoxyresin or silicone resin, can be used. For the light diffusing material,any known appropriate material, such as titanium oxide, silica, alumina,zinc oxide, or glass can be used. For the metal used as the lightreflecting material, for example, platinum (Pt), silver (Ag), rhodium(Rh), or aluminum (Al) can be used. Each sectioning member 21 a can beformed as a layer along the inner face of a sectioning groove 21, or canfill the sectioning groove 21 in whole or part. The upper part of thesectioning members 21 a can protrude higher than the upper face 20 a ofthe light guide member 20. In the present embodiment, for example, eachsectioning member 21 a in the form of a layer is disposed on the innerfaces of the sectioning groove 21.

A light source placement part 22 is a space in which a light source 30is disposed. In other words, the light source 30 is disposed in thelight source placement part 22. As will be explained later withreference to variations of the embodiment, a light source placement part22 can be a through hole passing through the light guide member 20 inthe Z direction, or a recessed part formed on the lower face 20 b of thelight guide member 20. In the present embodiment, the shape of the lightsource placement part 22 is a circle when viewed from above, but can be,for example, an ellipse or a polygon, such as a triangle, quadrilateral,hexagon, or octagon.

In the present embodiment, for example, each light source placement part22 is a through hole. A first light transmissive member 25 is providedin the light source placement part 22 so as to embed the light source 30disposed therein. For the first light transmissive member 25, forexample, a light transmissive resin material can be used. For the resinmaterial, similarly to the light guide member 20, a thermoplastic resinor thermosetting resin can be used.

A first light adjusting member 26 is provided on the first lighttransmissive member 25. The first light adjusting member 26 reflects aportion while transmitting a portion of the light emitted from the lightsource 30 that transmitted through the first light transmissive member25. The first light adjusting member 26 can be formed with, for example,a resin material containing a light diffusing material, or a metalmaterial. For example, for the resin material, a silicone resin, epoxyresin, or a resin combining these can be used. For the light diffusingmaterial, any known appropriate material, such as titanium oxide,silica, alumina, zinc oxide, or glass can be used. A dielectricmultilayer film can alternatively be used for the first light adjustingmember 26. In the present embodiment, for example, the first lightadjusting member 26 is disposed in the form of a film, but can bedisposed as dots. Moreover, the first light adjusting member 26 in thepresent embodiment covers the entire upper face of the first lighttransmissive member 25 when viewed from above, but a portion of theupper face of the first light transmissive member 25 can be exposed fromthe first light adjusting member 26.

A first light reflecting member 27 in the form of a film is disposed atthe bottom of each light source placement part 22, i.e., under the firstlight transmissive member 25. The first light reflecting member 27 isformed with a light reflecting material, such as a metal or a resincontaining a light diffusing material, similarly to the light reflectingmaterial contained in the sectioning member 21 a.

Instead of the first light reflecting member 27, the light reflectingsheet 206 on the wiring substrate 200 can be extended into the lightsource placement part 22 of the light guide member 20 when viewed fromabove. In this case, preferably, the light reflecting sheet 206 isextended to a position overlapping the light source 30 when viewed fromabove, i.e., between the light source 30 and the wiring substrate 200.This can hinder the wiring substrate 200 from absorbing a portion of thelight emitted from the light sources 30, thereby moderating theluminance decline around the light sources 30.

A light source 30 can be a light emitting element by itself, or astructure body in which a light emitting element and an optical membersuch as a wavelength conversion member are combined. As will beexplained later with reference to variations of the embodiment, a lightsource 30 can take a variety of forms.

In the present embodiment, each light source 30 includes a lightemitting element 31, a cover member 33, a second light transmissivemember 34, and a second light adjusting member 35. The light emittingelement 31 at least includes a semiconductor layers and a pair ofpositive and negative electrodes. The light emitting element 31, forexample, is a light emitting diode (LED), and emits, for example, bluelight. A semiconductor structure can include, for example,In_(x)Al_(y)Ga_(1-x-y)N (0≤x, 0≤y, x+y≤1). The light emitting element 31has a first face 31 a on which a pair of positive and negativeelectrodes is disposed, and a second face 31 b that opposes the firstface 31 a.

In the semiconductor structure body of a light emitting element 31, alight emitting diode structure body is achieved by stacking at least ap-type semiconductor layer, an emission layer, and an n-typesemiconductor layer, for example. The structure body of the emissionlayer can be one having a single active layer, such as a doubleheterostructure body and single quantum well (SQW) structure body, orone having a group of active layers such as a multi-quantum well (MQW)structure body. The emission layer can emit visible light or ultravioletlight. Examples of visible light include at least blue light to redlight. A semiconductor structure body that includes such an emissionlayer can include, for example, In_(x)Al_(y)Ga_(1-x-y)N (0≤x, 0≤y,x+y≤1).

The light emitting element 31 can include two or more emission layers inthe semiconductor structure body. For example, the semiconductorstructure body can be one that includes two or more emission layersbetween an n-type semiconductor layer and a p-type semiconductor layer,or one formed by repeating two or more structure bodies eachsuccessively stacking an n-type semiconductor layer, an emission layer,and a p-type semiconductor layer. Two or more emission layers caninclude those that emit light of different colors or the same color. Thesame emission color can be a range of emission colors that can be deemedas the same for the purpose of use, and for example, there can bevariation of about several nanometers in the dominant wavelength of eachemission color. A combination of emission colors can be suitablyselected. Examples of color combinations in the case of two emissionlayers include blue light and blue light, green light and green light,red light and red light, ultraviolet light and ultraviolet light, bluelight and green light, blue light and red light, green light and redlight, or the like.

The cover member 33, for example, is a resin material containing a lightdiffusing material, and is disposed in the surrounding of the lower partof the light emitting element 31. Specifically, for the cover member 33,a silicone or epoxy resin containing a light diffusing material, such astitanium oxide, silica, alumina, zinc oxide, or glass can be used. Aplanar light source 1 is provided with a bonding material 40 such assolder. The bonding material 40 connects the pair of positive andnegative electrodes of the light emitting element 31 to the connectionlayer 203 of the wiring substrate 200, but can connect to the wiringlayer 202 without via the connection layer 203.

The second light transmissive member 34 is disposed on the upper partof, around and above the light emitting element 31. The second lighttransmissive member 34 is formed of a light transmissive resin materialthat can contain a phosphor, but does not have to contain. For the resinmaterial used as the second light transmissive member 34, for example,an epoxy resin, silicone resin, or a resin mixing these can be used. Inthe case in which the second light transmissive member 34 contains aphosphor, the second light transmissive member 34 serves as a wavelengthconversion layer.

For the phosphors, yttrium aluminum garnet-based phosphors (e.g.,Y₃(Al,Ga)₅O₁₂:Ce), lutetium aluminum garnet-based phosphors (e.g.,Lu₃(Al,Ga)₅O₁₂:Ce), terbium aluminum garnet-based phosphors (e.g.,Tb₃(Al,Ga)₅O₁₂:Ce), β-SiAlON phosphors (e.g., (Si,Al)₃(O,N)₄:Eu),α-SiAlON phosphors (e.g., Mz(Si,Al)₁₂(O,N)₁₆ where 0<z≤2 and M is anelement selected from the group consisting of Li, Mg, Ca, Y, andlanthanide elements excluding La and Ce), nitride-based phosphors, suchas CASN-based phosphors (e.g., CaAlSiN₃:Eu) or SCASN-based phosphors(e.g., (Sr,Ca)AlSiN₃:Eu), fluoride-based phosphors, such as KSF-basedphosphors (e.g., K₂SiF₆:Mn) or MGF-based phosphors (e.g.,3.5MgO.0.5MgF₂.GeO₂:Mn), or quantum dot phosphors can be used.

The second light transmissive member 34 can contain several types ofphosphors. For example, containing a phosphor that absorbs blue lightand emits yellow light and a phosphor that absorbs blue light and emitsred light allows the light source 30 to emit white light. The secondlight transmissive member 34 can contain a light diffusing material tothe extent not to shield light. The content of the light diffusingmaterial in the second light transmissive member 34 can be adjusted suchthat the transmittance of the second light transmissive member 34 forthe light emitted from the light emitting element 31 is 50% to 99%,preferably 70% to 90%. For the light diffusing material, for example,titanium oxide, silica, alumina, zinc oxide, or glass can be used.

The second light adjusting member 35 is disposed on the upper face ofthe second light transmissive member 34. The second light adjustingmember 35, similarly to the first light adjusting member 26, is formedwith a light reflecting material, such as a metal or a resin materialcontaining a light diffusing material. The second light adjusting member35 reflects a portion and transmits a portion of the light entering fromthe second light transmissive member 34. In the case in which thetransmittance of the second light adjusting member 35 for the lightemitted from the light emitting element 31 is sufficiently low, forexample, 1% to 50%, preferably 3% to 30%, the second light adjustingmember 35 serves as a light shielding film, preventing the luminanceimmediately above the light source 30 from becoming excessively high.

Each light adjusting hole 23, similar to the sectioning grooves 21, canbe formed on the upper face 20 a or the lower face 20 b of the lightguide member 20, formed to pass through the light guide member 20 in theZ direction, formed as a shape in which a through hole is partiallyclosed, or as a hollow space not reaching the upper face 20 a or thelower face 20 b of the light guide member 20. In the present embodiment,for example, each light adjusting hole 23 is formed on the upper face 20a of the light guide member 20. In other words, the light adjustingholes 23 reach the upper face 20 a of the light guide member 20, but arepositioned apart from the lower face 20 b of the light guide member 20.

In the present disclosure, the term, “hole,” is a general designationfor a recessed part and a through hole. In other words, a “hole” can bea recessed part that does not pass through the body (e.g., the lightguide member 20) in which it is created, or a through hole that passesthrough the body. Furthermore, the shape of a “hole” is not limited. Inother words, it includes a high aspect ratio shape such as a grooveextending in one direction when viewed from above, a low aspect ratioshape such as a circular or polygonal shape when viewed from above, andany other regular or irregular shape therebetween. Moreover, theinternal structure of a “hole” can also be appropriately selected. Inother words, a “hole” includes one having an air layer inside, onehaving a certain member intentionally provided therein, and one in whichan unintended substance has been entered.

Each light adjusting hole 23 can occupy any percentage in the thicknessdirection of the light guide member 20. For example, in the case ofincreasing the amount of the light emitted from the light source 30 thatadvances towards the corners of the emission region R, the lightadjusting holes 23 preferably occupy at least 15%, more preferably atleast 25%, particularly preferably at least 50% of the thickness of thelight guide member 20.

The inside of each light adjusting hole 23 can be an air layer, orinclude a light transmissive material or light reflecting materialdisposed therein. In the case in which a light transmissive material isdisposed inside the light adjusting hole 23, the refractive index of thelight transmissive material is preferably lower than the refractiveindex of the light guide member 20. Examples of resins for use as thelight transmissive material or light reflecting material includethermoplastic resins, such as an acrylic resin, polycarbonate resin,cyclic polyolefin resin, polyethylene terephthalate resin, or polyesterresin, or thermosetting resins, such as an epoxy resin or siliconeresin. Moreover, the light transmissive material or light reflectingmaterial can contain a light diffusing material. For the light diffusingmaterial, any known appropriate material, such as titanium oxide,silica, alumina, zinc oxide, or glass can be used. For the metal used asthe light reflecting material, for example, platinum (Pt), silver (Ag),rhodium (Rh), or aluminum (Al) can be used. The light transmissivematerial or light reflecting material can be provided in the form of alayer along the inner face of a light adjusting hole 23, or can fill thelight adjusting hole 23 in whole or part. In the present embodiment, forexample, the inside of each light adjusting hole 23 is an air layer.Thus, the refractive index of the inside of each light adjusting hole 23is lower than the refractive index of the light guide member 20.

The planar arrangement of the light adjusting holes 23 will be explainednext.

For the purpose of explanation, an imaginary first straight line L1 andan imaginary second straight line L2 are established in the emissionregion R. A first straight line L1 is a straight line connecting thecenter 30 c of the light source 30 and a farthest point 21 b in thesectioning groove 21 that is farthest from the center 30 c of the lightsource 30, when viewed from above. A second straight line L2 is astraight line connecting the center 30 c of the light source 30 and aclosest point 21 c in the sectioning groove 21 that is closest from thecenter 30 c of the light source 30, when viewed from above.

The “center of the light source” is a geometric center when viewed fromabove, and in the case in which the shape of the light source 30 isquadrilateral, for example, the center 30 c is the intersection of thediagonal lines of the light source 30. “A farthest point 21 b in thesectioning groove that is farthest from the center of the light source”means a point in the sectioning groove 21 (i.e., sectioning groovesurrounding the light source 30) that is farthest from the center 30 cof the light source 30, where other sectioning grooves 21 surroundingonly other light sources 30 are not taken into consideration. In thecase in which the shape of the emission region R is quadrilateral, afarthest pint 21 b is a corner of the sectioning groove 21. In the casein which the shape of the emission region R is quadrilateral and thecenter 30 c of the light source 30 coincides with the center of theemission region R when viewed from above, there are four first straightlines L1 and four second straight lines L2.

The light adjusting holes 23 are not positioned on any first straightline L1. In the present embodiment, the light adjusting holes 23intersect with the second straight lines L2. The shape of each emissionregion R is quadrilateral when viewed from above, and the lightadjusting holes 23 are provided such that one light adjusting hole ispositioned between the light source 30 and each side of the emissionregion R.

When viewed from above, each light adjusting hole 23 is V-shaped, andthe bent part protrudes towards the light source 30. Each lightadjusting hole 23 has a first lateral face 23 a positioned closer to thelight source 30, and a second lateral face 23 b positioned opposite sideof the first lateral face 23 a. The first lateral face 23 a has a firstregion 23 c and a second region 23 d. The second region 23 d is obliqueto the first region 23 c. The normal line N1 normal to the first region23 c and the normal line N2 normal to the second region 23 d are bothoblique to a second straight line L2. The direction in which the secondregion 23 d is oblique to the second straight line L2 is opposite to thedirection in which the first region 23 c is oblique to the secondstraight line L2. For example, the shape of the light adjusting hole 23has line symmetry using the second straight line L2 as the axis ofsymmetry.

The width of such a light adjusting hole 23, for example, can be set toabout 1% to 5%, more preferably about 1.5% to 3% of the width of theemission region R. In the case of disposing the light transmissivematerial or light reflecting material described later in the lightadjusting holes 23, the width of each light adjusting hole 23 ispreferably set so that such a material is easily provided. The width ofa light adjusting hole 23 here is the shortest distance between thefirst lateral face 23 a and the second lateral face 23 b when viewedfrom above.

The operation of the planar light source according to the presentembodiment will be explained next.

FIG. 2 shows several examples of optical paths T.

When power is supplied to the light source 30 via the wiring substrate200, the light source 30 emits light. The light emitted from the lightsource 30, introduced into the light guide member 20 via the first lighttransmissive member 25, propagates in the light guide member 20 whilebeing reflected by the upper face 20 a and the lower face 20 b of thelight guide member 20.

A portion of the light propagating in the light guide member 20 reachesthe light adjusting holes 23. Because the refractive index of the insideof each light adjusting hole 23 is lower than the refractive index ofthe light guide member 20, depending on the angles of incidence on thefirst region 23 c and the second region 23 d of the first lateral face23 a, the light is totally reflected by the first region 23 c and thesecond region 23 d. A portion of the totally reflected light advancestowards the corners of the emission region R. This allows the light,that would have passed the locations of the light adjusting holes 23 ifabsent, to be totally reflected by the light adjusting holes 23 toadvance towards the corners of the emission region R. This, as a result,increases the brightness in the corners of the emission region R,thereby reducing luminance non-uniformity in the emission region R. Oncethe light reaches the sectioning groove 21, further propagation isobstructed by the sectioning groove 21. This hinders the light fromleaking into adjacent emission regions R.

The effect of the embodiment will be explained next.

In the present embodiment, sectioning grooves 21 are formed in the lightguide member 20 to section the emission face of the light emittingmodule 100 into a plurality of emission regions R. In the emissionregions R, light source placement parts 22 are respectively formed wherelight sources 30 are respectively disposed. The majority of the lightemitted from the light sources 30 exits through the upper face 20 of thelight guide member 20 before reaching the sectioning grooves 21.Accordingly, the majority of the light emitted by a light source 30exits the light emitting module 100 from the emission region R in whichthe light source 30 is disposed. This makes it possible to control theluminous intensity per emission region R. As a result, a high contrastimage can be displayed when a planar light source according to theembodiment is used as a light source for a liquid crystal display, forexample.

In the present embodiment, moreover, light adjusting holes 23 are formedin the light guide member 20, and light can be totally reflected by thelight adjusting holes 23. Because the corners of the emission regions Rare distant from the light sources 30, the corners of the emissionregions R are more likely to be dark in the absence of light adjustingholes 23.

Accordingly, in the present embodiment, light adjusting holes 23 areformed in the positions apart from the first straight lines L1, forexample, in the positions intersecting with the second straight linesL2. This allows a portion of the light propagating near the secondstraight lines L2 to be totally reflected by the light adjusting holes23 to advance towards the first straight lines L1. This can increase thebrightness in the corners of the emission regions R, thereby reducingluminance non-uniformity in each emission region R.

Second Embodiment

A second embodiment will be explained next.

FIG. 4 is a top view of an emission region of a planar light sourceaccording to the present embodiment.

As shown in FIG. 4 , in the planar light source 2 according to thepresent embodiment, the first lateral face 23 a of each light adjustinghole 23 is in contact with the light source placement part 22. Thesecond lateral face 23 b of each light adjusting hole 23 is positionedapart from the sectioning groove 21. This can also achieve a similareffect to that achieved by the first embodiment. In the presentembodiment, in particular, the light adjusting holes 23 disposed nearthe light source 30 can increase the amount of the light from the lightsource 30 that is totally reflected towards the corners of the emissionregion R. The other elements not described above, the operation, and theeffect of the present embodiment are similar to those of the firstembodiment.

Third Embodiment

A third embodiment will be explained next.

FIG. 5 is a top view of an emission region of a planar light sourceaccording to the present embodiment.

As shown in FIG. 5 , in the planar light source 3 according to thepresent embodiment, the first lateral face 23 a and the second lateralface 23 b of each light adjusting hole 23 are in contact with thecorresponding sectioning groove 21. The first lateral face 23 a of eachlight adjusting hole 23 is positioned apart from the light sourceplacement part 22. This can also achieve a similar effect to thatachieved by the first embodiment. In the present embodiment, inparticular, the light adjusting holes 23 positioned near the sectioninggroove 21 can increase the amount of the light from the light source 30that is totally reflected towards the corners and the vicinities of thecorners of the emission region R. The other elements not describedabove, the operation, and the effect of the present embodiment aresimilar to those of the first embodiment.

As illustrated with reference to the second and third embodiments, theratio of the distance between the light source placement part 22 and alight adjusting hole 23 to the distance between the light adjusting hole23 and the sectioning groove 21 can be adjusted in accordance withdesired light distribution characteristics. The light adjusting hole 23can be disposed in the central area between the light source placementpart 22 and the sectioning groove 21, can be closer to the light sourceplacement part 22 or the sectioning groove 21, or in contact with eitheror both of the light source placement part 22 and the sectioning groove21.

Fourth Embodiment

A fourth embodiment will be explained next.

FIG. 6 is a top view of an emission region of a planar light sourceaccording to the present embodiment.

As shown in FIG. 6 , in the planar light source 4 according to thepresent embodiment, the shape of each light adjusting hole 23 is a stripwhen viewed from above. The light adjusting holes 23 are arranged in thepositions and orientations such that at least a portion of the lightemitted from the light source 30 is totally reflected by the firstlateral faces 23 a to advance towards the corners of the emission regionR. For example, the first lateral faces 23 a of the light adjustingholes 23 are oblique to the X direction and the Y direction.

Furthermore, the light adjusting holes 23 are not disposed on any secondstraight line L2, but are each disposed in a region surrounded by afirst straight line L1, a second straight line L2, and the sectioninggroove 21. For example, a pair of adjacent light adjusting holes 23interposing a second straight line L2 is positioned to have linesymmetry using the second straight line L2 as the axis of symmetry. Thisallows the light adjusting holes to totally reflect the light from thelight source 30 towards the corners of the emission region R whileallowing a portion of the light from the light source 30 to propagatealong the second straight lines L2, thereby preventing the regionssurrounded by the second lateral faces 23 b of the light adjusting holes23 and the sectioning groove 21 from becoming excessively dark.Furthermore, a pair of adjacent light adjusting holes 23 interposing afirst straight line L1 is positioned to have line symmetry using thefirst straight line L1 as the axis of symmetry. The other elements notdescribed above, the operation, and the effect of the present embodimentare similar to those of the first embodiment.

Fifth Embodiment

A fifth embodiment will be explained next.

FIG. 7 is a top view of an emission region of a planar light sourceaccording to the present embodiment.

As shown in FIG. 7 , in the planar light source 5 according to thepresent embodiment, the shape of each light adjusting hole 23 whenviewed from above is triangular. In other words, the first region 23 c,the second region 23 d, and the second lateral face 23 b of each lightadjusting hole 23 form a triangle. The light adjusting holes 23 arepositioned apart from the first straight lines L1, and intersect withthe second straight lines L2. Similar to the first embodiment, theinside of each light adjusting hole 23 can be an air layer, or include alight transmissive material, or light reflecting material providedtherein. The other elements not described above, the operation, and theeffect of the present embodiment are similar to those of the firstembodiment.

Sixth Embodiment

A sixth embodiment will be explained next.

FIG. 8 is a top view of emission region of a planar light sourceaccording to the embodiment.

As shown in FIG. 8 , in the planar light source 6 according to thepresent embodiment, each first lateral face 23 a is convex-shaped,curved so as to outwardly protrude from the light adjusting hole 23. Forexample, the first lateral face 23 a is curved, protruding towards thelight source 30. The curvature of such a first lateral face 23 a, forexample, is preferably 0.08 to 0.35, more preferably 0.1 to 0.2. Eachlight adjusting hole 23 does not have line symmetrical shape using thesecond straight line L2 as the axis of symmetry. However, each lightadjusting hole 23 can have line symmetrical shape using the secondstraight line L2 as the axis of symmetry.

The portion of the light emitted from the light source 30 that enteredthe first lateral face 23 a of each light adjusting holes 23 at asmaller angle of incidence than the critical angle passes through thelight adjusting hole 23, while allowing the light that entered the firstlateral face 23 a at a larger angle of incidence than the critical angleto be totally reflected by the first lateral face 23 a to advancetowards a corner of the emission region R. At this point, the curvedfirst lateral faces 23 a that protrude towards the light source 30 candiffuse the totally reflected light.

In the present embodiment, the light propagated along the secondstraight lines L2 can be totally reflected by the first lateral faces 23a of the light adjusting holes 23. Allowing a portion of the lightreached the light adjusting holes 23 to pass through can prevent theregions behind the light adjusting holes 23 when viewed from the lightsource 30 from becoming excessively dark. The first lateral faces 23 athat are curved to protrude towards the light source 30 can diffuse thelight by way of total reflection. The other elements not describedabove, the operation, and the effect of the present embodiment aresimilar to those of the first embodiment.

Seventh Embodiment

A seventh embodiment will be explained next.

FIG. 9 is a top view of an emission region of a planar light sourceaccording to the present embodiment.

As shown in FIG. 9 , in the planar light source 7 according to thepresent embodiment, in addition to the components of the planar lightsource 1 according to the first embodiment, light adjusting holes 28 areformed at the upper face 20 a of the light guide member 20. Therefractive index of the inside of each light adjusting hole 28 is lowerthan the refractive index of the light guide member 20. The inside ofeach light adjusting hole 28, for example, is an air layer. When viewedfrom above, the light adjusting holes 28 are positioned to intersectwith the first straight lines L1. Furthermore, each light adjusting hole28 has a shape of a concave lens when viewed from above.

For example, when viewed from above, each light adjusting hole 28 canhave a shape of a plano-concave lens. In the example shown in FIG. 9 ,the first lateral face 28 a of each light adjusting hole 28 positionedcloser to the light source 30 is flat-shaped, and the second lateralface 28 b positioned closer to a corner of the emission region R isconcave-shaped, i.e., curved inward of the light adjusting holes 28.Conversely, the first lateral face 28 a can be concave-shaped, i.e.,curved inward of the light adjusting hole 28, and the second lateralface 28 b flat. Alternatively, when viewed from above, each lightadjusting hole 28 can have a biconcave lens shape. In other words, boththe first lateral face 28 a and the second lateral face 28 b of eachlight adjusting hole 28 can be concave-shaped, i.e., curved inward ofthe light adjusting hole 28.

Furthermore, each light adjusting hole 28 can have a shape of a concavemeniscus lens. In other words, the first lateral face 28 a can beconvex-shaped, curved outward so as to protrude towards the light source30, and the second lateral face 28 b concave-shaped, curved inward ofthe light adjusting hole 28. In this case, the curvature of the firstlateral face 28 a is smaller than the curvature of the second lateralface 28 b. Conversely, the second lateral face 28 a can beconvex-shaped, curved outward towards a corner of the emission region R,and the first lateral face 28 a concave-shaped, curved inward of thelight adjusting hole 28. In this case, the curvature of the secondlateral face 28 b is smaller than the curvature of the first lateralface 28 a.

In the present embodiment, at least one portion of the light emittedfrom the light source 30 that has reached the light adjusting holes 23is totally reflected by the first lateral faces 23 a of the lightadjusting holes 23. This allows a portion of the light that haspropagated near the second straight lines L2 to advance towards thefirst straight lines L1.

On the other hand, at least one portion of the light emitted from thelight source 30 that has reached the light adjusting holes 28 isrefracted as it passes through the light adjusting holes 28. At thistime, because the refractive index of the inside of each light adjustinghole 28 is lower than the refractive index of the light guide member 20,and the light adjusting holes 28 each have a concave lens shape, anoptical action similar to that of a regular convex lens results, therebyconverging the light that has passed through the light adjusting holes28. In this manner, the light passed through the light adjusting holes28 is converged towards the farthest points 21 b in the sectioninggroove 21 that is farthest from the center 30 c of the light source 30.

In this manner, the luminance in the corners of the emission region Rcan be further increased, and luminance non-uniformity in the emissionregion R can be further reduced. The other elements not described above,the operation, and the effect of the present embodiment are similar tothose of the first embodiment.

Eighth Embodiment

An eighth embodiment will be explained next.

FIG. 10 is a top view of an emission region of a planar light sourceaccording to the present embodiment.

As shown in FIG. 10 , in the planar light source 8 according to thepresent embodiment, a plurality of light sources 30 are disposed in eachemission region R. In the example shown in FIG. 10 , four light sources30 are disposed in each emission region R, and arranged in a matrix oftwo rows by two columns along the X and Y directions. In the planarlight source 8, four light source placement parts 22 are formed on thelower face of the light guide member 20, and each light source placementpart 22 is provided with a light source 30.

Moreover, eight light adjusting holes 23 are formed at the upper face 20a of the light guide member 20. The light adjusting holes 23 are notpositioned on any first straight line L1 that connects the center 30 cof a light source 30 and the farthest point 21 b in the sectioninggroove 21 that is farthest from the center 30 c. The light adjustingholes 23 can be positioned on the second lines L2 connecting the center30 c and the closest points 21 c in the sectioning groove 21 that isclosest from the center 30 c. As shown in FIG. 10 , it is preferable notto position any light adjusting hole 23 between the light sourceplacement parts 22.

According to the present embodiment, disposing a plurality of lightsources 30 in each emission region R can further reduce luminancenon-uniformity in each emission region R. The other elements notdescribed above, the operation, and the effect of the present embodimentare similar to those of the first embodiment.

Variations common to the embodiments described above will be explainedbelow.

The first to fifth variations described below are variations related tothe shapes of the sectioning grooves 21, the light source placementparts 22, and the light adjusting holes 23 in the up-down direction. Thesixth variation is an example in which a wiring substrate 200 is notdisposed. The seventh to twelfth variations are variations related tothe light sources 30. The drawings showing the variations below areschematic, in which certain elements might be omitted or simplified asappropriate. The embodiments described above and the variationsdescribed below can be implemented in combination.

First Variation

FIG. 11 is a cross-sectional view of a planar light source according toa first variation.

As shown in FIG. 11 , in the planar light source 11 of this variation,the sectioning groove 21 and the light adjusting holes 23 are formed onthe upper face 20 a side of the light guide member 20. In other words,the sectioning groove 21 and the light adjusting holes 23 reach theupper face 20 a of the light guide member 20, but are positioned apartfrom the lower face 20 b.

The sectioning groove 21 is filled with a sectioning member 21 acontaining a light reflecting material, and the inside of the sectioninggroove 21 is entirely buried under the sectioning member 21 a. The lightadjusting holes 23 are filled with an optical member 23 e containing alight transmissive material or light reflecting material, and the insideof each light adjusting hole 23 is entirely buried under the opticalmember 23 e. The upper edge of the sectioning member 21 a and the upperedges of the optical members 23 e are positioned higher than the upperface 20 a of the light guide member 20. The light source positing part22 is a recessed part formed on the lower face 20 b of the light guidemember 20. The light source placement part 22 can be entirely orpartially filled with a first light transmissive member 25, or can be anair layer. In this example, both the sectioning groove 21 and the lightadjusting holes 23 are illustrated such that the distance between theinner lateral faces of each sectioning groove 21 and the distancebetween the inner lateral faces of each light adjusting hole 23 increasetowards the top, however, the configurations are not limited thereto.The distance between the inner lateral faces of each sectioning groove21 and the distance between the inner lateral faces of each lightadjusting hole 23 can be increased towards the bottom, or remainsubstantially parallel in the Z direction.

Second Variation

FIG. 12 is a cross-sectional view of a planar light source according toa second variation.

As shown in FIG. 12 , in the planar light source 12 of this variation,the sectioning groove 21 and the light adjusting holes 23 are formed onthe lower face 20 b of the light guide member 20. In other words, thesectioning groove 21 and the light adjusting holes 23 are positionedapart from the upper face 20 a of the light guide member 20, but reachthe lower face 20 b. The inside of the sectioning groove 21 and thelight adjusting holes 23 are air layers. The light source placement part22 is a recessed part formed on the lower face 20 b of the light guidemember 20. The light source placement part 22 can be entirely orpartially filled with a first light transmissive member 25, or can be anair layer. FIG. 12 shows an example in which the inner lateral faces ofeach sectioning groove 21 and each light adjusting hole 23 aresubstantially parallel in the Z direction, however the configurationsare not limited thereto. The distance between the inner lateral faces ofeach sectioning groove 21 and the distance between the inner lateralfaces of each light adjusting hole 23 can be increased towards the topor bottom.

Third Variation

FIG. 13 is a cross-sectional view of a planar light source according toa third variation.

As shown in FIG. 13 , in the planar light source 13 of this variation,the sectioning groove 21 and the light adjusting holes 23 pass throughthe light guide member 20 in the up-down direction (Z direction). Inother words, the sectioning groove 21 and the light adjusting holes 23reach both the upper face 20 a and the lower face 20 b of the lightguide member 20. The inside of the sectioning groove 21 and the insideof the light adjusting holes 23 are air layers. The sectioning groove 21and the light adjusting holes 23 can be partially closed. The lightsource placement part 22 also passes through the light guide member 20in the up-down direction (Z direction). A first light transmissivemember 25 is provided in the light source placement part 22. On thefirst light transmissive member 25, a first light adjusting member 26 isdisposed. The first light transmissive member 25 and the first lightadjusting member 26 do not have to be provided, or only the first lighttransmissive member 25 can be provided without providing the first lightadjusting member 26. FIG. 13 shows an example in which the inner lateralfaces of each sectioning groove 21 and the inner lateral faces of eachlight adjusting hole 23 that pass through the light guide member 20 aresubstantially parallel in the Z direction, however, the configurationsare not limited thereto. The distance between the inner lateral faces ofeach sectioning groove 21 and the distance between the inner lateralfaces of each light adjusting hole 23 can be increased towards the top,or can be increased toward the bottom.

Fourth Variation

FIG. 14 is a cross-sectional view of a planar light source according toa fourth variation.

As shown in FIG. 14 , in the planar light source 14 of this variation,the sectioning groove 21 and the light adjusting holes 23 are formed onthe upper face 20 a of the light guide member 20. Furthermore, oneportion of the sectioning groove 21 in the Z direction is closed to forma closed portion 21 h. One portion of each light adjusting hole 23 inthe Z direction is closed to form a closed portion 23 h. In the closedportions 21 h and 23 h, the lateral faces of the groove or hole are incontact, or the distance between the lateral faces of the grove or holeis smaller than the remaining portion.

Only one or the other of the closed portion 21 h and the closed portions23 h can be formed. Moreover, the closed portion 21 h can be formedacross the entire lengths, or only in certain portion(s) of the lengths,in the directions in which the sectioning groove 21 is elongated (i.e.,the X and Y directions). Similarly, the closed portion 23 h can beformed across the entire length, or only in certain portion(s) of thelength, in the direction in which a light adjusting hole 23 extends(i.e., the direction parallel to the X-Y plane). Furthermore, theposition of a closed portion 21 h or 23 h in the Z direction can beappropriately determined.

Fifth Variation

FIG. 15 is a cross-sectional view of a planar light source according toa fifth variation.

As shown in FIG. 15 , in the planar light source 15 of this variation,the sectioning groove 21 and the light adjusting holes 23 are formed inthe light guide member 20. In other words, the sectioning grove 21 andthe light adjusting holes 23 are positioned apart from both the upperface 20 a and the lower face 20 b of the light guide member 20. Theinside of the sectioning groove 21 and the inside of the light adjustingholes 23 are air layers. The light source placement part 22 passesthrough the light guide member 20 in the up-down direction (Zdirection).

Such a light guide member 20 can include a lower light guide plate andan upper light guide plate. The upper face of the lower light guideplate is provided with a recessed part that will become the lowerportion of the sectioning groove 21, recessed parts that will become thelower portions of the light adjusting holes 23, and a through hole thatwill become the lower portion of the light source placement part 22. Thelower face of the upper light guide plate is provided with a recessedpart that will become the upper portion of the sectioning groove 21,recessed parts that will become the upper portions of the lightadjusting holes 23, and a through hole that will become the upperportion of the light source placement part 22. Such a light guide member20 can be formed by adhering a lower light guide plate and an upperlight guide plate together. A first light transmissive member 25entirely or partially fills the light source placement part 22. On thefirst light transmissive member 25, a first light adjusting member 26 isprovided.

Sixth Variation

FIG. 16 is a cross-sectional view of a light emitting module accordingto a sixth variation.

As shown in FIG. 16 , in the light emitting module 116 of thisvariation, no wiring substrate 200 is provided. In the light guidemember 20, the light source placement part 22 is a recessed part formedon the lower face 20 b of the light guide member 20. The light source 30is disposed in the light source placement part 22, and an affixingmember 29 is provide in the space between the light source 30 and thelight guide member 20 in the light source placement part 22. Theaffixing member 29, for example, is formed of a light transmissive resinmaterial. The light source 30 is fixed to the light guide member 20 viathe affixing member 29.

The sectioning groove 21 is formed on the lower face 20 b of the lightguide member 20, and a sectioning member 21 a is provided insidethereof. The sectioning member 21 a reaches the light source placementpart 22. A pair of wirings 120 is disposed on the lower face of thesectioning member 21 a. The pair of wirings 120 is electricallyconnected to the pair of positive and negative electrodes of the lightemitting element 31 of the light source 30 via a pair of externalelectrode members 210. The light adjusting holes 23 are formed at theupper face 20 a of the light guide member 20. A recessed part 121 iscreated in the region of the upper face 20 a of the light guide member20, the region of the upper face 20 a including the area immediatelyabove the light source placement part 22. A first light adjusting member26 can be provided in the recessed part 121, but does not have to beprovided.

The light emitting module 116 of this variation constructs a planarlight source by being mounted on an external substrate (not shown).Power is supplied to the light source 30 from the external substrate.

Seventh Variation

FIG. 17A is a cross-sectional view of a light source according to aseventh variation.

As shown in FIG. 17A, in the light source 30A of this variation, a lightemitting element 31, a cover member 33, and a second light transmissivemember 34 are provided. A pair of external electrode members 210 isconnected to the pair of positive and negative electrodes disposed onthe first face 31 a of the light emitting element 31. The cover member33 is disposed under the first face 31 a of the light emitting element31 around the external electrode members 210. The second lighttransmissive member 34 covers the lateral faces 31 c and the second face31 b of the light emitting element 31. The second light transmissivemember 34 can be a wavelength conversion layer containing a phosphor.

Eighth Variation

FIG. 17B is a cross-sectional view of a light source according to aneighth variation.

As shown in FIG. 17B, the light source 30B of this variation differsfrom the light source 30A of the seventh variation in that the covermember 33 covers the lateral faces 31 c of the light emitting element31, the second light transmissive member 34 is disposed on the secondface 31 b of the light emitting element 31, and a second light adjustingmember 35 is disposed on the second light transmissive member 34. In thecase in which the transmittance of the second light adjusting member 35is sufficiently low, the second light adjusting member 35 serves as alight shielding film.

Ninth Variation

FIG. 17C is a cross-sectional view of a light source according to aninth variation.

As shown in FIG. 17C, the light source 30C of this variation differsfrom the light source 30B of the eighth variation in that no secondlight adjusting member 35 is provided.

Tenth Variation

FIG. 18A is a cross-sectional view of a light source according to atenth variation.

As shown in FIG. 18A, the light source 30D of this variation differsfrom the light source 30A of the seventh variation in that it does notinclude any cover member 33 or second light transmissive member 34, butincludes a light shielding layer 36. The light shielding layer 36 isdisposed on the second face 31 b of the light emitting element 31. Thelight shielding layer 36, for example, is a metal layer or a distributedBragg reflector (DBR). The light shielding layer 36 can be formed of aresin containing a light diffusing material.

Eleventh Variation

FIG. 18B is a cross-sectional view of a light source according to aneleventh variation.

As shown in FIG. 18B, the light source 30E of this variation differsfrom the light source 30A of the seventh variation in that a lighttransmissive layer 37 is provided instead of the second lighttransmissive member 34, and a light shielding film 38 is furtherprovided. The light transmissive layer 37, for example, is formed of alight transmissive resin layer. The light transmissive layer 37, forexample, does not substantially contain a phosphor. The lighttransmissive layer 37 can contain a light diffusing material. The lightshielding film 38 is disposed on the light transmissive layer 37. Thelight shielding film 38, for example, is a metal layer or a distributedBragg reflector. The light shielding film 38 can be a resin containing alight diffusing material.

Twelfth Variation

FIG. 18C is a cross-sectional view of a light source according to atwelfth variation.

As shown in FIG. 18C, the light source 30F of this variation differsfrom the light source 30E of the eleventh variation in that the covermember 33 covers the lateral faces 31 c of the light emitting element31, and the light transmissive layer 37 is disposed on the second face31 b of the light emitting element 31.

In the embodiments and the variations described in the foregoing, thelight guide member 20 was illustrated as a plate-shaped member, but isnot limited to this. The light guide member 20 can be a layer formed tocover the light sources 30. The light guide member 20 can have amultilayer structure body or as blocks provided per emission region R.Moreover, a light source 30 can have a plurality of light emittingelements. Furthermore, the shape of each emission region R is notlimited to quadrilateral, and can be polygonal other than quadrilateral,such as triangular or hexagonal.

What is claimed is:
 1. A light emitting module comprising: a light guidemember comprising: a sectioning groove defined by a first lateralsurface and a second lateral surface, an emission region defined by thesectioning groove, a light source placement part located in the emissionregion, a first light adjusting hole, and a second light adjusting hole,wherein, in a schematic top view, the first light adjusting hole and thesecond light adjusting hole are located between the sectioning grooveand the light source placement part; and a light source disposed in thelight source placement part, wherein: in the schematic top view: thefirst light adjusting hole is not positioned on a first straight lineconnecting (i) a center of the light source and (ii) a point in thesectioning groove that is farthest from the center of the light source,the first light adjusting hole has a first lateral face located on aside closer to the light source and a second lateral face located on aside opposite the first lateral face, the first lateral face has a firstregion, a line normal to the first region is oblique to a secondstraight line connecting (i) the center of the light source and (ii) apoint in the sectioning groove that is closest to the center of thelight source, and the second adjusting hole has a first lateral face,and a second lateral face that is curved inward towards the firstlateral face.
 2. The light emitting module according to claim 1, whereina refractive index of an inside of the first light adjusting hole islower than a refractive index of the light guide member, and the firstregion is configured to totally reflect light emitted from the lightsource.
 3. The light emitting module according to claim 1, wherein aninside of the first light adjusting hole is an air layer.
 4. The lightemitting module according to claim 1, wherein the first light adjustinghole is positioned to intersect with the second straight line.
 5. Thelight emitting module according to claim 1, wherein: in the schematictop view: the emission region has a quadrilateral shape, and the firstlight adjusting hole and the second light adjusting hole are provided atpositions between the light source and sides of the emission region. 6.The light emitting module according to claim 1, wherein: in theschematic top view: the first lateral face of the first light adjustinghole further has a second region oblique to the first region, and a linenormal to the second region is oblique to the second straight line. 7.The light emitting module according to claim 6, wherein the secondregion is configured to totally reflect light emitted from the lightsource.
 8. The light emitting module according to claim 6, wherein adirection in which the line normal to the second region is oblique tothe second straight line is opposite to a direction in which the linenormal to the first region is oblique to the second straight line. 9.The light emitting module according to claim 6, wherein, in theschematic top view, the first region, the second region, and the secondlateral face of the first light adjusting hole form a triangle.
 10. Thelight emitting module according to claim 1, wherein, in the schematictop view, the first region is positioned in a region surrounded by thefirst straight line, the second straight line, and the sectioninggroove.
 11. The light emitting module according to claim 1, wherein, inthe schematic top view, the first lateral face of the first lightadjusting hole is convex-shaped so as to be curved outward away from thesecond lateral face.
 12. The light emitting module according to claim 1,wherein the first light adjusting hole reaches an upper face of thelight guide member, but is positioned apart from a lower face of thelight guide member.
 13. The light emitting module according to claim 1,wherein the first light adjusting hole passes through the light guidemember from an upper face to a lower face of the light guide member. 14.The light emitting module according to claim 1, further comprising: anadditional light adjusting member disposed in an area immediately abovethe light source placement part at an upper face of the light guidemember, the additional light adjusting member being configured toreflect a portion of the light emitted from the light source andtransmit a portion of the light emitted from the light source.
 15. Thelight emitting module according to claim 1, wherein: the light sourcecomprises a light emitting element, and the light emitting element has afirst face on which a pair of positive and negative electrodes areformed, and a second face located opposite to the first face.
 16. Thelight emitting module according to claim 15, wherein the light emittingelement further comprises a light shielding layer positioned on thesecond face.
 17. The light emitting module according to claim 15,wherein: the light source further comprises: a light transmissive layerpositioned at least on the second face of the light emitting element,and a light shielding film disposed on the light transmissive layer. 18.The light emitting module according to claim 15, wherein the lightsource further comprises a wavelength conversion layer disposed at leaston the second face of the light emitting element.
 19. The light emittingmodule according to claim 18, wherein the light source further comprisesa light shielding film disposed on the wavelength conversion layer. 20.The light emitting module according to claim 1, wherein a distancebetween the first lateral surface and the second lateral surfaceincreases towards a top of the sectioning groove.
 21. The light emittingmodule according to claim 1, further comprising: a light reflectingmaterial that includes a first portion disposed on the first lateralsurface defining the groove and a second portion disposed on the secondlateral surface defining the groove.
 22. The light emitting moduleaccording to claim 1, wherein the first lateral face of the second lightadjusting hole is flat.
 23. A planar light source comprising: the lightemitting module according to claim 1, and a wiring substrate; wherein:the light guide member is disposed on the wiring substrate, and thelight source is mounted on the wiring substrate.
 24. A light emittingmodule comprising: a light guide member comprising: an emission regiondefined by the sectioning groove, a light source placement part locatedin the emission region, a first light adjusting hole, and a second lightadjusting hole, wherein, in a schematic top view, the first lightadjusting hole and the second light adjusting hole are located betweenthe sectioning groove and the light source placement part; and a lightsource disposed in the light source placement part, wherein: arefractive index of an inside of the second light adjusting hole islower than a refractive index of the light guide member, in theschematic top view: a shape of the emission region is quadrilateral, thefirst light adjusting hole is not positioned on a first straight lineconnecting a center of the light source and a corner of the emissionregion, wherein light emitted from the light source is totally reflectedby a lateral face of the first light adjusting hole, the second lightadjusting hole is positioned at a region with which the first straightline intersects, wherein light emitted from the light source isrefracted in the second light adjusting hole, and the second adjustinghole has a first lateral face, and a second lateral face that is curvedinward towards the first lateral face.
 25. The light emitting moduleaccording to claim 24, wherein a distance between the first lateralsurface and the second lateral surface increases towards a top of thesectioning groove.
 26. The light emitting module according to claim 24,further comprising: a light reflecting material that includes a firstportion disposed on the first lateral surface defining the groove and asecond portion disposed on the second lateral surface defining thegroove.
 27. The light emitting module according to claim 24, wherein thefirst lateral face of the second light adjusting hole is flat.